Field of the Invention
The invention relates to a field of antithyroid ointment drugs for external application, and more particularly to a preparation method for an antithyroid ointment for external application.
Description of Related Art
Hyperthyroidism is a common disease, and in the last seventy years, oral imidazole and thiourea antithyroid drugs (oral antithyroid drugs in the following context) have been the first choice and main treatment method for hyperthyroidism. The method is slower in controlling hyperthyroidism, the efficacy is not stable enough, some systemic adverse reactions may be produced, and the remission rate is lower after drug use is discontinued. Therefore, in 1993, Ling Chen, et, al., developed and applied for the invention patent “Antithyroid cream for external application” and have been granted a patent, with the patent number ZL93111370.9. The patent disclosed an oil-in-water cream containing an antithyroid drug and glucocorticoids, and the application of the cream on skin on the thyroid to treat hyperthyroidism produced better effects than oral antithyroid drugs, and no significant systemic side effects were observed. In clinical applications, it was found that significant adverse skin reactions occurred on the application site on the neck of many hyperthyroidism patients using the antithyroid cream for external application, and therefore the application of the drug was significantly limited.
Therefore, Ling Chen further applied for the invention patent “External-applied ointment used for treating thyropathy, and its preparing method” in 2005, which was also granted a patent, with the patent number is ZL200510070954.0. The patent disclosed an oil-in-water cream containing an antithyroid drug, glucocorticoids, a percutaneous penetration enhancer, an oleaginous base, a water-soluble base, a preservative, and an antioxidant as raw materials. This agent produced less local skin adverse reactions than the agent of patent 1, but preclinical studies showed that, the stability of glucocorticoids, one of the main drugs, was poor, and the efficacy and shelf life of the agent were affected. Moreover, it was found from more clinical applications for more patients and a longer period that, a greater occurrence of local skin adverse reaction still existed, which affects the compliance of patients to treatment.